1. Field
Exemplary embodiments of the present invention relate to a semiconductor device and a method for fabricating the same, and more particularly, to a semiconductor device including conductive interconnections formed through a damascene process and a method for fabricating the same.
2. Description of the Related Art
A semiconductor device includes various interconnections formed in a plurality of layers and contacts for connecting interconnections in different layers. For example, a bit line is connected to a specific part under a bit line contact through a bit line contact disposed thereunder. FIG. 1 briefly illustrates the semiconductor device.
FIG. 1 is a cross-sectional view of a conventional semiconductor device.
Referring to FIG. 1, a first interlayer dielectric layer 11 includes a plurality of bit line contacts 12 provided therein. The plurality of bit line contacts 12 may be arranged at even intervals.
Over the first interlayer dielectric layer 11 having the plurality of bit line contacts 12 provided therein, a second interlayer dielectric layer 13 is disposed. The second interlayer dielectric layer 13 includes a plurality of bit lines 14 provided therein. Each bit line 14 is arranged to contact with a corresponding bit line contact 12, respectively.
The bit line 14 may be formed of copper (Cu) to reduce resistance. In this case, because Cu is not dry-etched, the bit line 14 is inevitably formed through a damascene process of burying a conductive material in a space where an insulating layer is etched.
Recently, with the increase in integration degree of semiconductor devices, the pitch of interconnections has been reduced. However, when the pitch of interconnections formed in a plurality of layers is reduced, an alignment margin between the bit line 14 and the corresponding bit line contact 12 decreases. Accordingly, a distance (as referred to symbol A) between a bit line contact 12 and another bit line 14 adjacent to the corresponding bit line 14 decreases. In this case, a bridge may occur between the bit line contact 12 and the adjacent bit line 14.